1. Field of the Invention
The present invention relates to an entry detection apparatus and more particularly to either a screen or a barrier bar which is not only expandable, but which also incorporates a conductive wire for connection to an alarm circuit.
2. Description of the Prior Art
U.S. Pat. No. 4,285,383, entitled Adjustable Vehicle Screen, issued to Ronald L. Steenburgh on Aug. 25, 1981, teaches an adjustable vehicle screen which utilizes a telescoping frame having a slot disposed in the innermost surface thereof so as to permit an elastic-like screen to have the marginal edge thereof pass therein. The free edges of the screen are captured within the tubular telescoping frame. The frame may be dimensional so as to accommodate various window openings in motor vehicles by allowing the screen to expand or contract in size in conformity therewith. The adjustable vehicle screen may utilize a pair of hinges joining together a pair of U-shaped frame members so as to permit the screen element to be folded up when it is not in use. Each of the U-shaped frame members has telescoping components in order to permit the adjustable vehicle screen to adjust in size for various window openings. A portion of the frame has a protrusion which extends outwardly therefrom so that the adjustable vehicle screen can be installed within the groove which is located in the frame of the vehicle in which the uppermost edge an the side edges of the window may reside. The lowermost region of the frame portion has a channel therein which receives the uppermost regions of the glass of the vehicle, when the glass window in a retracted position. The protrusion portions and the groove portion serve to maintain the frame securely in the window opening when the adjustable vehicle screen is thus installed therein.
U.S. Pat. No. 4,279,288, entitled Adjustable Frame Apparatus, issued to George C. Lacier on Jul. 21, 1981, teaches a storm window apparatus which is adjustable to fit various sizes of window and which includes a mitered right angle frame components that are hinged for easy assembly without tools. The frame members fit telescopicly within each other for adjustability.
U.S. Pat. No. 4,381,255, entitled Modular Interior Storm Window and Heat Trap, issued to Henry L. Long on Mar. 9, 1982, teaches a window insulation device for interior installation which includes at least two tubular sections, and at least one male and one female section. The male and female sections are adjustably fitted for tight reception between the window sill and the window frame.
U.S. Pat. No. 4,146,293, entitled Entry Detection Screen, issued to Robert E. Mutton and Dennis E. Riordan on Mar. 27, 1979, teaches an entry detection screen which is sometimes referred to as a protective screen which includes a screen mesh and a conductive wire. The conductive wire which may be connected to an alarm circuit is sewed onto the screen mesh in order to fix it in place. One form of the alarm circuit includes double conductive wires so that two series alarm circuits can be provided. The double conductive wires can be twisted to make the following circuit more difficult. A twist in the of the double wires can be made under a frame section where it cannot be seen by an intruder.
U.S. Pat. No. 3,051,935, entitled Protective Screen, issued to Clarence P. Wilson on Aug. 28, 1962, teaches an alarm screen which includes a frame which is to be mounted on a building enclosing structure, a sheet of non-conductive screen mesh which has its marginal portion secured to the frame and two strands of conductive wire which are spaced apart and which are interwoven in the screen mesh with each of the strands having an end portion terminating adjacent to the frame.
U.S. Pat. No. 3,495,054, entitled Supply Parts for Making Various Plug and Jack Burglar Alarm Switch Constructions, issued to Lawrence N. Lea on Feb. 10, 1970, teaches an electrical switch which is used in the normally closed protective circuit of a burglar alarm system.
U.S. Pat. No. 3,863,242, entitled Electric Screen Protection, issued to James W. Minton on Jan. 28, 1975, teaches an alarm screen frame which has projections with sharp edges which are struck out of the peripheral frame of a screen. An electrical conductor is attached to plural projections and traverses the screen, so that when a nominal physical force is exerted upon the conductor the force will cause it to break at a sharp projection. A circuit is connected to the conductor in order to actuate an alarm when the conductor is broken.
In the prior are there is a barrier bar which includes a first tubular member and a second tubular member, which is telescopically inserted in the first tubular member and which a spring resiliently biases, and which is installed in a window frame with the spring resiliently secures the barrier bar therein against the sides of the window frame. The barrier bar has a jacketed lead which is connected to an alarm system. The problem with the barrier bar is that it is possible for a potential burglar to move the barrier bar parallel to the sides of the window frame in order to enter the premises through the window frame which is to be protected by the barrier bar.